1909.] Physiological Properties of Tetrachlorethane, etc. 225 



It will be observed from the above numbers that the action of tri- 

 chlorethylene on the muscle can be represented practically, except at the end, 

 by a straight line,* the geometrical figure being approximately a right- 

 angled triangle, whereas that of chloroform is initially an area bounded by a 

 convex and a concave surface, and finally becomes triangular. 



Though cases in which the rate of chemical change is a linear function 

 of time are rare, yet they have been observed, especially with solutions 

 of very great dilution.f Such a result would not, therefore, exclude the 

 action of trichlorethylene on muscle from the category of chemical change. 



As regards the recoveries, that from the chloroform was, at first, more 

 pronounced, but generally a diminution set in, and in some cases a con- 

 tracture more or less marked, which put an end to the record. On the 

 other hand, that from the trichlorethylene started slowly and proceeded 

 regularly. The measurements of one such recovery are given ; at the point 

 called " interval " it was necessary to reset the travelling plate and marker 

 for a higher line ; the time would be about two to three minutes. 



Time. 

 » 



Recovery in 

 millimetres 

 (observed). 



Time. 



Recovery in 

 millimetres 

 (observed). 



Time. 



Recovery in 

 millimetres 

 (observed.) 



0 



0 



0 



6 



12 



9-5 



2 



3 



2 



7* 



14 



9-5 



4 



4 



4 



7-5 



16 



10 



6 



5 



6 



8 -0 



18 



10 -5 



Interval 





8 



8 -5 



20 



11 







10 



9 



22 



11 -5 



From these figures it is clear that after the first interval the recovery 

 increases uniformly at the rate of 1 mm. per two minutes at the earlier 

 stage, and of 0'5 mm. per two minutes at the latter stage, the difference 

 between these two rates being probably an effect of fatigue. But, however 

 this may be, the recovery from trichlorethylene is more regular than that 

 from any other drug examined by this method. 



* From an inspection of numerous records it appears probable that an arc of a curve 

 has become almost coincident with its chord ; the result is quite analogous with certain 

 cases of chemical change. 



t Veley, ' Chem. Soc. Trans.,' 1909, vol. 95, p. 1188. 



